From what has been said under the article Impotentia, q. v., the physician will be sufficiently directed in his judgment; nor need wc enlarge with the disgusting indecency with which the old authors expatiate on this subject, nor on the public display of the active powers in the venereal act, which some of the canons enjoined. The original authors seem plainly to hint that this indecency was only the prelude, like the modern actions for crim. con. to a divorce, and designed as a justification of the most licentious conduct; for divorces, they add, were less frequent since such exhibitions were abolished. This practice began, it is said early in the thirteenth century, and ended about a hundred and fifty years afterwards.

Poisons. This frequent cause of violent and premature death is often the subject of inquiry in courts of judicature, and the physician is usually called on for his opinion. Science has been often disgraced by the crude, the injudicious, and often the opposite, opinions offered on these occasions; nor has humanity had less cause to regret the sacrifice of lives on the most vague and inconclusive evidence. Poisons may be accidental or designed. We shall begin with the latter.

The marks that poison has been administered are the sudden appearance of extraordinary and unsuspected symptoms, as uneasiness, nausea, an acute pain in the stomach, palpitations, fainlings, disagreeable and fetid eructations, vomiting of blood, and bile, hiccough, sudden debility, smallness and inequality of the pulse, cold and clammy sweats, coldness of the extremities, paleness, livid nails, general oedematous swellings, windy distention of the abdomen, sudden relief with an equally rapid return of pains, blackness and swelling of the lips, burning thirst, loss of voice, a livid countenance, vertigo, convulsions, rolling and starting eyes, loss of sight, with a dilated pupil, lethargy, suppression of urine, a fetid smell of the whole body, purple eruptions, livid gangrenous spots, and an alienation of mind. All these symptoms are undoubtedly equivocal, and occasionally attend other diseases. They arc marks of poison only when they come on suddenly, without any known cause; when the food, if unsuspected as the vehicle, sudden cold, violent affections of mind, or deleterious vapours, cannot be accused; for these will induce many of the symptoms, though seldom in so considerable a degree as arises from poison.

If the patient be not a suicide, and still retains his senses, he can explain the taste of the food, or medicine, which has induced these symptoms, so as to direct the future inquiries. When no satisfactory explanation can be obtained we must depend on the evidence collected on dissection. Poisons, so far as they are the object of our present inquiry, are violent, inflammatory, stimulants, or sedatives. The pungent stimulants betray themselves by the taste, the pain in swallowing, and the inflammation of the fauces; and they must be treated under the head of accidental poison, as they cannot be given without suspicion. The chief substance to be considered here is arsenic, which is nearly tasteless, and violent in its action, even in trifling doses. Its power is shown by violent inflammation and gangrene in the stomach; and it is discovered by calcining the contents of the stomach with the black flux, when the smell of garlic will betray even such an impregnation as will not often be fatal. Some of the saline mercurials show no very decided action on the tongue or fauces, and will produce similar effects. These may be discovered by adding ammonia, and heating the whole in a close vessel, when the mercury will be so far revived as to whiten copper on rubbing. In this way mercury can be often discovered in those quack medicines where its existence is utterly denied; for the ammonia contri-bates to precipitate the mercury, reduced in part to its metallic state, and enables it to appear on the copper. The suspected substance, if arsenical, heated between plates of copper, will give a whitish tinge to the part of the plates in contact with it. Independent of these. trials, when the stimulant poisons have been the cause of death, the abdomen is greatly inflated, becomes rapidly putrid, dark spots appear on the body, erosion, inflammation, and gangrene, are found in the fauces and stomach, the blood is black and collected in the veins; above all, the villous coat of the stomach is destroyed. One other discriminating appearance, on dissection, is mentioned by a respectable author on jurisprudence. If, after a body has been long buried, should gangrened spots be found in the stomach, surrounded by a reddish circle, these were effects of changes during life. Should the colour of the whole be uniform, the putrefaction took place after death.

There are other poisons which kill by a partial stimulus. The chief of these is cantharides; but their pecu-har action on the bladder will point out the cause. The violent inflammation, the rapidity with which it hastens to gangrene, will at once betray the crime, and, at the same time, point out the culprit. No such can escape. The colocynth, the elatcrium, and the tithymali, betray themselves by their taste, as well as by their local action, and can neither escape the detection of the person himself who is the subject of the crime, nor the attendant physician.

The narcotic poisons like the others, produce vomiting; but the faintness which is the effect of the vomiting in the former cases is the apparent cause of it in the present. The rapidly sinking strength, the dilated pupil, convulsions, stupor, sleep, vertigo, swelling veins, and cold extremities, point out the cause. Fortunately there are few such substances that do not betray themselves by their taste; but there are such, though we shall not point them out; nor shall we mention any poison that can be secretly administered. It is incumbent, however, on the practitioner to be cautious in these instances respecting his decisions; for no chemical analysis will assist him, and his only guide will be the discharge of substances which the powers of the stomach cannot change. He must compare with anxious attention the appearance of the symptoms after the supposed cause; trace with diligent circumspection every other circumstance that might have produced the effect; examine with care the patient's usual habits, his predispositions, his complaints, and at last remember that every medical conclusion is doubtful. Should he then be positive when the life of a human creature is at stake ? One trial has been falsely considered to be decisive, viz. the effects of what might remain of the supposed fatal beverage on animals. This will hold true of the stimulant poisons; but by no means of the narcotic. The most innocent substances of this kind are occasionally fatal to animals; the narcotics, most injurious to man, are to many animals innocuous; and the human fluids changed by putrefaction are themselves poisonous.